WO2007119944A1

WO2007119944A1 - Composition of hydraulic oil using vegetable oil

Info

Publication number: WO2007119944A1
Application number: PCT/KR2007/001641
Authority: WO
Inventors: Kyung-Man Yeom; Young-Rang Heo
Original assignee: Suman Co., Ltd.
Priority date: 2006-04-19
Filing date: 2007-04-04
Publication date: 2007-10-25
Also published as: KR100691614B1

Abstract

A marine hydraulic oil contains vegetable oil, a dryer, a film-forming inhibitor, and an adhesion promoter, and is an environmentally preferred over conventional mineral hydraulic oils for a jack-up tool used in the block manufacturing and assembly processes for a new ship under construction because time and expenses spent on a coating operation for removing leaked oil during the work can be markedly reduced.

Description

COMPOSITION OF HYDRAULIC OIL USING VEGETABLE OIL

Technical Field The present invention relates to a marine hydraulic oil. More specifically, the present invention relates to a marine hydraulic oil, which contains vegetable oil, a dryer, a film-forming inhibitor, and an adhesion promoter, and which is an environmentally preferred over conventional mineral hydraulic oils for a jack-up tool used in the block manufacturing and assembly processes for a new ship under construction because time and expenses spent on a coating operation for removing leaked oil during the work can be markedly reduced.

Background Art:

A hydraulic oil is a power transmission medium of hydraulic systems used in diverse types of equipment in industries, construction machinery and so on. The hydraulic oil for use in a hydraulic system is largely divided into petroleum-based hydraulic oil and non-flammable hydraulic oil. The petroleum-based hydraulic oil is divided again into normal hydraulic oil, NC hydraulic oil, anti-wear hydraulic oil, etc. The non-flammable hydraulic oil is divided into hydrous oil and synthetic hydraulic oil.

For efficient and smooth performance, the hydraulic oil should have optimum viscosity and high viscosity index. When viscosity of the hydraulic oil is not adequate, an oil leakage is most likely to occur, a machine wears may wear down, or a precise, smooth operation may not be possible, only degrading the efficiency of the machine. Therefore, selection of the hydraulic oil having an optimum viscosity according to a device's type, size and temperature is very important in order to make the hydraulic system work the best. Moreover, to maintain the optimum viscosity being selected, viscosity index needs to be high so that viscosity may not be so sensitive to a change in temperature.

In addition, superior oxidation stability is another property the hydraulic oil should have because a sludge produced from severe oxidation of the hydraulic oil causes a valve for example to get clogged up or to wear down in its contact area. Generally, agitation or pressure intensification of the hydraulic oil results in friction loss and an increase in the amount of foam, which in turn raises the temperature. Since oxidation of the hydraulic oil is promoted by an increase in temperature, high oxidation stability is essential to maintain stable hydraulic oil efficiency.

Other properties, besides the above, the hydraulic oil needs are foam resistance, anti-corrosion, and the like. As the pressure fluctuates repeatedly in a hydraulic system, air may enter the hydraulic oil, leading to severe bubble formation. This not only degrades the performance of equipment but also causes operational errors. Therefore, the hydraulic oil should have foam resistance to be able to defoam quickly. Also, the hydraulic oil needs to be resistant to corrosion or have a corrosion preventive property to be able to prevent corrosion on metal surfaces in contact with the hydraulic oil.

The most commonly used hydraulic oil that meets the requirements mentioned above is a mineral hydraulic oil such as petroleum-based hydraulic oil. The mineral hydraulic oil is used in a wide range of applications because it is excellent in fluidity, has a viscosity not heavily depending on a change in temperature, suffers less chemical and physical transformations despite long-term use. In particular, hydraulic systems installed in ships and vessels that are usually exposed to different environmental temperatures must use a hydraulic oil having high viscosity index. For this reason, mineral hydraulic oils are preferred over conventional synthetic oils.

However, the existing mineral hydraulic oil may contaminate the ocean and is a hazardous substance to human body. Therefore, it should be treated with caution and if in any chance oil leakage occurs during work, instead of coating a leaked site directly, the leaked oil needs to be removed or cleaned up first.

Especially, in case of a jack-up tool used in the block manufacturing and assembly processes for constructing a new ship, in which a coating operation is carried out following the application of mineral hydraulic oil, leaked mineral hydraulic oil is removed or washed out with a special solvent, or is burned by flames of an oxygen cutting machine. Then, blasting pretreatment should be performed as part of the secondary treatment process. These take a lot of work hours and money.

Therefore, there is a need to develop a new hydraulic oil that has superior fluidity and high viscosity index comparable to mineral hydraulic oil, does not cause much contamination to the environment, is low in toxicity to human body, and can substantially reduce time and expenses spent on the removal of hydraulic oil at a contaminated area prior to coating a leaked site on a ship.

Disclosure

Technical Problem

Therefore, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a marine hydraulic oil capable of reducing marine environmental pollution and toxic impacts of exposure.

Another object of the present invention is to provide a marine hydraulic oil for a jack-up tool used in the block manufacturing and assembly processes for constructing a new ship that requires a coating operation after the application of hydraulic oil, and for markedly reducing time and expenses spent on the removal of leaked hydraulic oil. Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Technical Solution

In order to accomplish the above-mentioned objects, there is provided a marine hydraulic oil, which contains vegetable oil, a dryer, a film-forming inhibitor, and an adhesion promoter.

Vegetable oil in this invention is for ensuring lubricativeness of hydraulic oil. The vegetable oil is preferably selected, but is not limited to, from a vegetable oil group consisting of castor oil, coconut oil, cottonseed oil, dehydrated castor oil, fish oil, linseed oil, safflower oil, sunflower oil, soybean oil, tall oil fatty acid, tung oil, and CADURA E-IO. The vegetable oil preferably has an iodine value in a range of 50 to 200. If iodine value exceeds 200, film may be formed on the surface or impurities may be produced during the use of hydraulic oil, leading to a decrease in storage stability. On the other hand, if iodine value is below 50, the vegetable oil leaked on a ship is not dried by oxidation. Thus, vegetable leakage sites cannot be coated with paint.

The oxidation dryer, one of ingredients of the marine hydraulic oil of the invention is for enabling a coating operation even if hydraulic oil may have been contaminated. The oxidation dryer is preferably selected from a metallic dryer group that consists of cobalt alkylate, plumbum alkylate, manganese alkylate, calcium alkylate, zinc alkylate, and zirconium alkylate.

The oxidation dryer should be suitable for drying surface as well as inside. A preferable content of the oxidation dryer is in a range of 0.1 to 10% by weight of the vegetable oil. In case that the oxidation dryer content is 0.1% or below, drying by oxidation is not activated well. Meanwhile, in case that the oxidation dryer content is 10% or above, the oil dries during storage, so it cannot be applied as hydraulic oil.

The film-forming inhibitor, another ingredient of the marine hydraulic oil of the invention, is for inhibiting the production of impurities despite long-term use of hydraulic oil. An oxime group additive is preferably used as the film- forming inhibitor at an amount of 0.1 to 5% by weight of the vegetable oil. In case that the content of the film-forming inhibitor is 0.1% or below, film is formed or impurities are produced after long-term use of the hydraulic oil. On the other hand, in case that the content of the film-forming inhibitor is 5% or above and that a ship is contaminated by leaked hydraulic oil, the ship is not dried by oxidation, only interfering with a coating process of paint.

The adhesion-promoter, another element of the marine hydraulic oil of the invention, is for increasing interlayer adhesion between the hydraulic oil and paint. A preferable content of the adhesion-promoter is in a range of 0.1 to 3% by weight of the vegetable oil. For example, PAP-500

(manufactured by AFC Korea, Korea) , which has an epoxide functional group being hardened with paint, a molecular weight in a range of 500 to 1000 to be dried by oxidation, an iodine value of 90-120, and a certain degree of unsaturation, is preferably used.

Advantageous Effects

The marine hydraulic oil according to the present invention is capable of reducing marine environmental pollution and toxic impacts of exposure. Moreover, it is capable of substantially reducing time and expenses spent on the removal of leaked hydraulic oil during construction of a new ship that requires a coating operation after the application of hydraulic oil.

Best Mode The following describes examples of the preparation of marine hydraulic fluid according to the present invention and test results on properties thereof. While the invention is described in conjunction with various examples, they are illustrative only. Accordingly, many alternative, modifications and variations will be apparent to persons skilled in the art in light of the foregoing detailed description. The foregoing description is intended to embrace all such alternatives and variations.

Example 1: Preparation of Marine Hydraulic Oil lOOOg of linseed oil, 50Og of soybean oil, and lOOg of tung oil were added to a 21, 4 neck standard flask. A stirrer magnet was dropped, and a thermometer and a condenser were inserted in the flask to prepare a mixed solution. While stirring the mixed solution, lβg of methyl ethyl ketoxime, 1Og of 8% cobalt naphthenate, lβg of 24% Pb naphthenate, and lβg of PAP-500 adhesion-promoter were added to finally obtain hydraulic oil having an iodine value in a range of 145 to 165.

Example 2 : Preparation of Marine Hydraulic Oil

75Og of linseed oil, 75Og of soybean oil, and lOOg of tung oil were added to a 21, 4 neck standard flask. A stirrer magnet was dropped, and a thermometer and a condenser were inserted in the flask to prepare a mixed solution. While stirring the mixed solution, lβg of methyl ethyl ketoxime, 1Og of 8% cobalt naphthenate, lβg of 24% Pb naphthenate, and lβg of PAP-500 adhesion-promoter were added to finally obtain hydraulic oil having an iodine value in a range of 140 to 160. Example 3: Preparation of Marine Hydraulic Oil

60Og of linseed oil, 50Og of soybean oil, and 50Og of dehydrate castor oil were added to a 21, 4 neck standard flask. A stirrer magnet was dropped, and a thermometer and a condenser were inserted in the flask to prepare a mixed solution. While stirring the mixed solution, lβg of methyl ethyl ketoxime, 1Og of 8% cobalt naphthenate, 1Og of 24% Pb naphthenate, βg of 6% manganese naphthenate, and lβg of PAP-

500 adhesion-promoter were added to finally obtain hydraulic oil having an iodine value in a range of 135 to 155.

Example 4: Preparation of Marine Hydraulic Oil

80Og of soybean oil, 70Og of dehydrate castor oil, and lOOg of coconut oil were added to a 21, 4 neck standard flask. A stirrer magnet was dropped, and a thermometer and a condenser were inserted in the flask to prepare a mixed solution. While stirring the mixed solution, lβg of methyl ethyl ketoxime, 1Og of 8% cobalt naphthenate, 1Og of 24% Pb naphthenate, βg of 6% manganese naphthenate, and lβg of PAP- 500 adhesion-promoter were added to finally obtain hydraulic oil having an iodine value in a range of 115 to 135.

Example 5: Preparation of Marine Hydraulic Oil

30Og of linseed oil, 70Og of soybean oil, 50Og of dehydrate castor oil, and lOOg of coconut oil were added to a

21, 4 neck standard flask. A stirrer magnet was dropped, and a thermometer and a condenser were inserted in the flask to prepare a mixed solution. While stirring the mixed solution, 16g of methyl ethyl ketoxime, 1Og of 8% cobalt naphthenate, 1Og of 24% Pb naphthenate, βg of 6% manganese naphthenate, and lβg of PAP-500 adhesion-promoter were added to finally obtain hydraulic oil having an iodine value in a range of 120 to 140.

Example 6: Tests on Properties of Marine Hydraulic Oils Prepared To test properties of marine hydraulic oils obtained from Examples 1 to 5, a front surface of a ship was contaminated with the hydraulic oil of the invention and removed by using a mop. For comparison, a conventional synthetic hydraulic oil (manufactured by Power team Co., Ltd, USA) , a widely used phosphoric ester type marine hydraulic oil, was prepared.

The front surface of a ship to which the hydraulic oil was applied was divided into 6 sheets of test pieces, each being treated with SIS 05 5900 Sa 2.5 and having a size of 100x300mmx3t, for each coating specification, and tests were repeated. The test pieces were subjected to a primer coating (mineral shop-primer fragment at 20μm or epoxy paint fragment at lOOμm) , .dried for 24 hours at room temperature, and contaminated by the hydraulic oil. The contaminated hydraulic oil was mopped, and the test pieces were air dried for 20 days. Next, surfaces of the test pieces had a finish coating with an epoxy paint fragment at lOOμm, and air dried for 24 days.

The test pieces were treated with the marine hydraulic oil of the invention and the conventional synthetic hydraulic oil according to the conditions described, and went through tests of items that are normally evaluated after coating ship hulls. Table 1 below shows evaluation results. It should be noted that seawater resistance of each test piece was evaluated first because of the nature of a ship, and then physical properties of test pieces were measured.

[Table 1]

In Table 1, numerical values among evaluation items indicate grades equivalent to test methods, or numerical values by evaluation criteria used for test methods.

That is, seawater resistance is data for checking problems that occur on a fragment surface after test pieces were subjected to repetition of the soaking/drying cycle for 120 days, i.e., soaking in seawater for 5 days and drying for 2 days at room temperature. It reveals changes in color under visual inspection, blister occurrence to the fragments under ASTM D714 conditions, and rust formation on the fragment surfaces under ASTM D610 conditions. Moreover, adhesion of a fragment was measured by using Dolly test method of ASTM D4541, and impact resistance of a fragment was measured by using a method of ASTM G 14. Industrial Applicability

As apparent from the above description, the marine hydraulic oil containing vegetable oil is capable of reducing marine environmental pollution and toxic impacts of exposure. Moreover, when applied to the jack-up tool used in the block manufacturing and assembly processes for constructing a new ship that requires a coating operation after the application of hydraulic oil, only part of the hydraulic oil leak, if any, may be removed and dried by oxidation. Therefore, a great amount of work hours and money can noticeably be reduced, compared with the use of conventional mineral hydraulic oils whose contaminated cites are removed or washed out with a special solvent, or are burned by flames of an oxygen cutting machine, followed by blasting pretreatment as part of the secondary treatment process.

Claims

1. A marine hydraulic oil, containing vegetable oil, a dryer, a film-forming inhibitor, and an adhesion promoter.

2. The marine hydraulic oil of claim 1, wherein the vegetable oil is selected from a group consisting of castor oil, coconut oil, cottonseed oil, dehydrated castor oil, fish oil, linseed oil, safflower oil, sunflower oil, soybean oil, tall oil fatty acid, tung oil, and CADURA E-IO.

3. The marine hydraulic oil of claim 1, wherein the vegetable oil has an iodine value in a range of 50 to 200.

4. The marine hydraulic oil of claim 1, wherein the oxidation dryer selected from a group consisting of cobalt alkylate, plumbum alkylate, manganese alkylate, calcium alkylate, zinc alkylate, and zirconium alkylate.

5. The marine hydraulic oil of claim 1, wherein a content of the oxidation dryer is in a range of 0.1 to 10% by weight of the vegetable oil.

6. The marine hydraulic oil of claim 1, wherein the film-forming inhibitor includes an oxime group additive, and is contained in the vegetable oil at 0.1 to 5% by weight.

7. The marine hydraulic oil of claim 1, wherein the adhesion-promoter contains an epoxide functional group and is and is contained in the vegetable oil at 0.1 to 3% by weight.